In a one-way fluid valve, fluid is permitted to flow freely, with little resistance, in one direction, referred to as forward flow. Fluid is also generally prevented from flowing in the opposite direction through the valve, referred to as backflow, i.e. the valve presents a high resistance to fluid backflow.
Examples of such one-way valves include reed valves and conventional poppet check valves. Reed valves use thin flaps of metal, referred to as reeds, to cover a supply port to limit fluid backflow when the pressure at the supply port is less than the delivery pressure. When the pressure at the supply port is greater than the delivery pressure, the reeds bend to permit forward fluid flow through the valve.
Conventional poppet check valves include a moving poppet member which covers the supply port to limit fluid backflow when the pressure at the supply port is less than the delivery pressure. When the pressure at the supply port is greater than delivery pressure, the poppet member moves to uncover the supply port to permit forward flow of the fluid through the valve.
Reed valves and poppet check valves have known disadvantages. The thin metal reeds in the reed valves fatigue and break, due to high cycle bending in use. The poppets in the poppet check valves are typically heavy and hence have large inertia, so that they are not useful in applications that require high frequency cyclical operation. Further, conventional poppet check valves have complex flow paths, requiring special purpose housings. Off-the-shelf commercial components and material cannot be used to make poppet check valves.
Accordingly, it is desirable to have a reliable and long-lived one-way valve that is inexpensive and capable of high-frequency cyclical operation.